A possible benefit of fiction is that it leads you to experience emotions vicariously that it would be much more expensive to experience for real, yet the vicarious experience is realistic enough that it serves as useful practice, a way of "taming" the emotions. Textbooks don't convey emotions.

I seem to recall this argument from a review of Cloverfield, or possibly the director's commentary. Broadcast images such as from the 9/11 aftermath generated lots of anxiety, and seeing similar images - the amateurish, jerky camcorder type - reframed in a fictional setting which is "obviously" over the top helps you, the audience, come to terms with the reality.